Toddler Laws of Physics (Toddler Lessons: Part One)

They may live by their own rules most of the time, but even toddlers can’t escape the laws of physics.

Here are ten laws of physics as demonstrated by toddlers. (Well, eight laws of physics/laws connected to physics, and two random principles favoured by scientists, technically.)

1. Archimede’s Principle

(The buoyant force exerted on a body immersed in a fluid is equal to the weight of the fluid that the body displaces. The volume of an object can be calculated by the volume of water it displaces.)

Measuring the displacement of water by a toddler in a bath allows accurate calculation of the volume of work involved in cleaning the bathroom following said bath.

2. Boyle’s law

(When temperature is constant, volume of a gas is inversely proportional to the pressure.)

The volume of sleep a toddler has is inversely proportionate to the pressure of the temper tantrum in which the toddler will engage.

3. Newton’s Law of Universal Gravitation

(The force with which bodies are attracted to each other is directly proportional to the product of their masses, and inversely proportional to the square of the distance between them.)

The attraction of two toddlers to one another is directly proportional to the likelihood of them hitting one other, and inversely proportional to the likelihood of there being two of the toy they will both want to play with.

4. Pascal’s Law

(Pressure exerted at any point in a confined fluid is transmitted equally at every other point in the container.)

Tantrums exerted by a toddler in any shop during an outing will be transmitted equally throughout all shops on the outing (until the parent surrenders and returns home, or supplies chocolate).

5. Newton’s Laws of Motion

(First Law: An object at rest will remain at rest, and an object in motion will continue to move at a constant velocity, unless acted upon by an external force. Second Law: The sum of the external forces on an object is equal to the mass of that object multiplied by the acceleration of the object. Third Law: When one body exerts a force on another body, the other body exerts a force equal in magnitude and opposite in direction on the first body.)

Toddler’s First Law of Motion: A moving toddler will continue moving at a constant velocity (known as ‘hyperactive cheetah’) until acted upon by the external force of a wall that came out of nowhere and smacked them in the nose. A toddler who does not wish to sit in the buggy will enter and remain in a state of extreme rest (known as ‘the plank’) until acted upon by the external force of bribery with raisins and wrestled into the buggy.

Toddler’s Second Law of Motion: High speed toddlers brandishing heavy objects with the intent of whacking you on the head are very dangerous.

Toddler’s Third Law of Motion: Two toddlers running will always run with equal zeal in opposite directions, exerting equal force upon each other at the point of inevitable collision. They will both cry.

6. The Theory of Special Relativity

(What is relative and what is absolute about space, time and motion…Oh, yes, I am not even attempting to give a proper summary of the Theory of Special Relativity!)

Bedtime is relative: where parents see bedtime, toddlers do not. Broccoli is relative: parents see food, toddlers do not. Everything a parent says is actually relative. It may have been an order from the parents’ point of view. The toddler, however, heard a gentle suggestion that they have decided not to follow.

Furthermore, according to the Theory of Special Relativity, moving clocks run more slowly than stationary clocks. Grumpy toddlers are also able to influence the speed with which clocks run. This is why an hour in the doctors’ surgery waiting room lasts for approximately eleven years.

7. Uncertainty Principle

(In quantum mechanics, two complementary parameters (eg, energy and time) cannot both be understood to infinite accuracy: the more you know about one, the less you know about the other.)

Toddlers are their own Uncertainty Principle: the more a parent believes they know about what their toddler wants, the less they actually know. This is why your toddler is crying because they asked for a jam sandwich and you gave them a jam sandwich.

8. Causality Principle

(Cause must always precede effect.)

Causality does apply to toddlers, but not as we know it. Every effect has an alleged cause, but it is not necessarily relevant in any way and it might not have happened yet.
‘Why is the baby in a toy storage box?’
‘Because I’m going to wear my wellies tomorrow, aren’t I?’

9. Occam’s Razor*

(The hypothesis with the fewest assumptions, providing the simplest answer, should be selected.)

Now, toddlers disapprove of Occam’s Razor. They prefer the most ludicrous explanation imaginable for any given situation. However, toddlers are walking manifestations of the principle. They are the simplest explanation. Jam on the baby? Toddler did it. Shoes in the bread bin? Toddler did it. Crayon on the tv? ‘Peppa wanted to be blue’ = Toddler did it.

According to Occam’s Razor, if it looks like a toddler did it, the toddler did it. Do not be fooled by spurious accusations about the cat’s involvement.

10. Murphy’s Law

(If anything can go wrong, it will.)

Self explanatory: in parenting toddlers, if anything can go wrong (and it can), it will.


(Please Note: Absolutely no level of scientific accuracy should be assumed in the contents of this post. If you are studying the Theory of Relativity, step away: nothing here is going to help you. Though, interestingly, if a great enough mass of toddlers are concentrated in any area, they DO create a black hole from which no toy that enters will ever emerge. But I digress…into nonsense, I may add, not General Relativity. Step away.)


You can see other posts in my Toddler Lessons series here.


    • Silly Mummy says:

      Haha! I think at that point, you enter Schrodinger’s Naughtiness – both siblings exist in a dual state of naughty and innocent until the parent identifies a culprit!

  1. Jules says:

    Haha! This amused me greatly – whilst simultaneously making me fear the toddler years (which fortunately are quite a way off at the moment!) #thelist

    • Silly Mummy says:

      Toddlers can be hard work, but they are certainly amusing! I quite like toddlers (don’t tell anyone!), but I have yet to reach the 3 year point, which many say is the worst!

    • Silly Mummy says:

      Aw thank you! I’m definitely not a scientific genius (& will probably be told how wrong I am if anyone who is reads this), but my toddler science is definitely accurate! πŸ˜€

  2. Lee Gaitan says:

    This was hilarious and so very clever! Posts like this make me realize I might not be so nostalgic for my long ago days of mothering a toddler as I often think I am. Now grandmotherhood…I think I could get on board with that!

    • Silly Mummy says:

      Thank you! Yes, toddlers are hard work, but they are funny. My mum loves grandmotherhood! They save their most charming behaviour for the grandparents too!

    • Silly Mummy says:

      Thanks! I’ve never had a dog, but I can imagine that is very true! Washing a cat deserves it’s own scientific law I think, which can be summarised as ‘don’t do it’.

  3. Tori says:

    Love this one: “The volume of sleep a toddler has is inversely proportionate to the pressure of the temper tantrum in which the toddler will engage.” Unfortunately there is so much truth to this, all the way from babyhood to school age. Tired kids are just plain dicks. Great post! Very original. #justanotherlinky

  4. El says:

    Hahaha, perfect…Now I understand these Laws much better but I still prefer the Toddler’s version so that I can laugh. Thank goodness it’s the Tween’s and Teenager’s Laws at mine now! #PoColo

    • Silly Mummy says:

      Thank you! Yes, that sounds much like it usually goes for us. The eldest meanwhile likes to run circuits of the waiting room, chatting to people. She does not understand that she is less charming to sick people. If prevented from this activity, she will join in the screaming!

  5. Charlotte says:

    Haha I am also enjoying some of the toddlers laws of physics! including Occams razor! where currently everything involves either a jedi, alien or horse as an explanation for everything including who dropped the toast on my carpet! Thanks so much for linking up at #KCACOLS. Hope you come back again next Sunday

  6. Alice says:

    Well that explains EVERYTHING!
    How did you know Jet cried when I gave him the jam sandwich he asked for!? He isn’t even a toddler anymore – I think these laws may be more universal than we first thought…
    x Alice

  7. Wyn says:

    Fantastic. I have a fellow dad at my twins club, who like me is a science geek. I will share this with him. You should consider making a poster of this, I would put it in my office. πŸ™‚

  8. Mrs Tubbs says:

    Love it! We live the one where Lego expands to fill all the available floor space regularly. Even one tiny box will fill a floor. Not sure what law it is, but it’s mine now.

  9. Miranda says:

    This is so SO funny! My toddler had a complete melt-down over lunch yesterday because she didn’t want what we were having, she only wanted a jelly sandwich. So I finally gave in and made her a jelly sandwich, only to then have her throw a fit about why she didn’t get the same lunch as everyone else.

    Seriously. I can’t make this stuff up. Glad I’m not the only one with toddler problems.

  10. I remember so many of these, the plank! UG! The worst! At that point you just want to carry them back to the car and go home, or the tantrum in the store! I can just see the Toddler as a scientist, she’s got all these theories down!

    The one I remember most though was cleaning up after bath time. When I was too tired to care I would let them splash away. I needed the few minutes this bought me to just relax, but crawling around cleaning up the floor afterwards wasn’t really worth it, or was it? LOL

  11. Kimmie says:

    Your ability to consistently come up with such brilliantly written, cleverly thought out (not to mention hilarious) posts never ceases to amaze me. Such a gift!

    I love #6… 11 years… at least! πŸ˜‰

  12. Kaye says:

    Another hilarious post. I’m not that keen on science but these laws I can definitely relate with. Thanks for linking up to #MarvMondays. Kaye xo

  13. Love this – and a lot of it sounds familiar. Especially Newton’s Laws of Motion, My daughter often just keeps running until she smacks into something because she wasn’t looking where she was going, and then she seems very confused as to where the object has come from. #fortheloveofBLOG

  14. Elizabeth says:

    Hahaha! So true! I’m on toddler number 4 now, with a baby that will come along behind (ah, why do I torture myself). The triggers are always different, but meltdowns never change!

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