Can It Change Back?

Aligned to 2-PS1-4 — Next Generation Science Standards.

What this lesson teaches

Heating or cooling can change things — some changes can go back the way they were, and some cannot.

Example 1

Water freezes into ice and can melt back into water, but a cooked egg can never turn back into a raw egg.

Example 2

Melted butter can cool and harden again, but burnt toast can never become bread.

Example 3

Ask whether you can undo it. Squashing clay can be undone; baking it into a hard pot cannot.

Watch an ice cube melt and tell if it could freeze again.
Sort these into 'can change back' or 'cannot': melting butter, burning toast, freezing juice.
Explain why toasting bread cannot be undone.

Every lesson comes with a video taught in English and Spanish — the same video the QR code in the printed workbook opens.

Calentar o enfriar puede cambiar las cosas — algunos cambios pueden regresar a como estaban antes y otros no.

Ejemplo 1: El agua se congela en hielo y puede derretirse de nuevo en agua, pero un huevo cocido nunca puede volver a ser un huevo crudo.

Ejemplo 2: La mantequilla derretida se puede enfriar y endurecer otra vez, pero el pan quemado nunca puede volver a ser pan.

Ejemplo 3: Pregúntate si se puede deshacer. Aplastar plastilina se puede deshacer; hornearla hasta volverla una olla dura, no.

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