Scrovegni Chapel timing

They only allow you about 20 minutes inside the chapel, as you may gather from the time slots. But first you will sit in a climate controlled room for 20 minutes to equalize the temperature and humidity, then your group will be allowed in for 20 minutes and then must exit to allow the next group in.

PS. there should be nothing magical about 16:14 departure, since there are Regionale trains to Venice S. Lucia about every 10 minutes for 4.10 EUR, rather than taking the expensive Freccia train. Some of these are Regionale Veloce's which do it in the same amount of time. They even have 1st class for 6.15 EUR. The Veloce's go every half hour at 21 and 51 past the hour. And no reservations. Just stamp your ticket and get on the train.

The Chapel is well worth a visit. The beauty that fills such a small space is amazing. Honestly what I have done, and continue to do, is book a visit timed with my arrival in Padova and then book a visit towards the end of my day. The train station is right down the street, an easy walk (or use the tram). Because they allow you so little time in the chapel itself I find that 2 trips give me a better chance to appreciate what I am seeing. All that said and the truth be told: I am not a museum-type visitor. The Chapel is an exception for me . . . a much enjoyed exception.

Sitting in the climate-controlled room prior to entering is more interesting than it sounds, because you watch a video about the restoration of the Chapel. But anyway, yes, the whole visit takes ~40 minutes.

When we were there a few years ago, the ticket was a combo with a nearby museum. You might want the 14:00, so you could browse through the museum afterwards and head to the train station which is just north of the Scrovegni Chapel area.

Robert, you have a great idea. I was a bit overwhelmed at how much there is to look at in this very small chapel. The frescoes are jaw-dropping. I wanted way more time in there but I totally understand the conservation need. I was with a RS Village Italy tour and the local guide really kind of pushed the time, I think we had maybe 25 or 30 minutes (not a busy day) and it was incredible.

I agree with the suggestion on the 1400 time frame.

I would turn your day around ...
Book the Scrovegni Chapel for around 10am, as it between the station and the centre.
Then before lunch, choose from ... Duomo, Baptistery, Piazza dei Signori ,Caffe Pedrochhi, Palazzo Bo (university), Palazzo della Ragione (with Piazza della Frutta and Piazza dell’Erbe on either side)
Then after lunch, choose from ... Basilica di Sant Antonio, botanic gardens (Orto Botanico), Prato della Valle
Take the tram to return to the station from where you will find frequent departures for Venice.

DJP:
That schedule probably makes more sense but I was thinking of the heat in July, and that it might be better to do outdoor things in the morning and the Chapel (which I presume is climate controlled) in the heat of the afternoon.

I was in Padua 22+23 July 2012 and it was pleasantly warm, not excessively hot. It was very nice late afternoon walking the botanic gardens (Orto Botanico) and the Prato della Valle. I would not have liked to reach the Scrovegni Chapel feeling icky and with sweat dripping, to enter the aircon for just 30mins, before coming back out into the heat. That's my preference though. Padova is lovely. Enjoy.

I do what Robert does, but I book tickets with one time gap. Although seeing the Chapel in different light, early and late, is a great idea.

Do get the combo ticket. I don't think there are that many "outdoor" sights in Padua, I remember going in and out a lot. Presumably the indoors will be cool - either AC or the naturally cool churches. Walk slowly, eat granita (it is more cooling than gelato).